Attachment-plug.



W. A. STACEY.

ATTACHMENT PLUG.

APPLICATION FILED APR.27. ms.

1,292,911, Patented Jan. 28, 1919.

511 100 n-To: 4 11 2150) $1 flll'ozylewy,

WILLIAM A. STACEY, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE BRYANT ELECTRIC CORPORATION OF CONNECTICUT.

COMPANY, A.

i FFGE.

Specification of Letters Patent.

Patented Jan. 28, 1919.

Application filed April 27, 1918. Serial No. 281,134.

To all whom itmay concern:

Be it known that I, WILLIAM A. Smear, a citizen of the United States of America, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Attachment-Plugs, of which the following is a specification.

- My invention relates to attachment plugs, and the object of my invention is to provide a plug of novel construction fitting it for heavy duty, and having an associated device for gripping the wire cable to prevent undue strains upon the wire terminal connections.

Referring to the accompanying drawing, Figure 1 is a side elevation of a plug in which my invention is embodied in one form; Y

Fi 2 is a vertical section therethrough on the line 2-2, Fig. 1;

Fig. 3 is a top plan of the plug; Fig. 4 is an inverted plan thereof with one of the combined wire terminal plates and plug jacks removed; and

Fig. 5 is a side elevation of the cable 7 clamp.

naily pierced The plug here shown to illustrate my invention comprises a relatively heavy body 10 of insulating material, preferably of molded insulating composition, long1tud1 at 11 to afiord an entrance hole for the cable 12 opening to a chamber 13 to recve a strain-relief knot, flanked by ledges 14. On these ledges are secured wire terminal plates 15 and 16, carrying binding having integral therewith a jacks 18 which project beyond the end of t e pluglbody. The plates 15 and 16 are preferably eld in position by means of rivets 19, around the serrated heads and shanks of which the molded material is cast, leaving projecting ends to be spun over the outer faces of the terminal plates, as illustrated in Figs. 2 and 4. At the cable end of the body a neck 20 is formed, and the heavy end flange 21 is recessed on opposite sides to afford a shallow channel 22.

lower end of the cable hole 11 an annular flange 24 which limits the entry of the cable lnto the plug and prevents wire beards from the sheath 23 from straying into the wiring chamber, while, at the same time, leaving ample passageway for the insulated wires 25 which are embedded in the cable. While the usual strain-relief knot 26 in the wires .aflords considerable protection against dis-.

turbance of the binding screw connections thereof to the terminal plates 15 and 16, it 1s highly desirable to provide further protection for these connections a ainst strains .due not only to the longitu inal pull on the cable, but also to twisting of the cable with relation to the plug; and for this purpose I propose to rovlde the'plug with a clamping device W ich firmly engages the cable and holds it rigid with relation to the plug body. I

This cable clamp, as here shown, comprlses a pair of clamping members, each having a semi-circular strap 27 adapted to he in the channel 20 forming the neck of the plug below the flange 21 of the latter, a bridging stra 28 adapted to lie in the channel 22 in the ange 21, and a cable clamping strap 29 adapted to partially surround the cable beyond the end of the plug. Lugs 30 on the straps 27 and lugs 31 on the straps -29 are tapped to receive draw-up screws 32 sheath 23. f The clamp may be secured by the straps 27 to the plug in advance of the wiring of the latter, leaving the straps 29 loose to permit the insertion of the cable. Where such practice is followed, it is desirable to flare the outer margins of the straps 29, as at 35, to guide the cable into the hole 11 in the plug. After the cable has been inserted and shoved down against the limiting flange 24 at the bottom of the hole 11, the straps 29 are tightened and the wiring connections to the terminal plates 15 and 16 then completed. It is obvious that after the straps 29 have been drawn up firmly against the cable 23, it is impossible to twist the latter with relation to the plug, since the enthe other hand, the straps 29 I gagement of the e "pieces 28 in the channel 22 prevents t e notation of. the clamp with relation to the plu Similarly, the engagement of the straps 2 in the channel 20 against the flange 21 prevents endwise separation of the cable from'the pl 7 and thereby aids in protecting the termina clamp'may be in the form of a split ring, it

is preferable to use fairly heavy sheet metal stock and stamp therefrom the clampelements in the form shown, both halves of the clamp being identical and thus necessitating but a single set of forming dies. I claim V 1. An attachment plug having an insulat ing body with constricted neck and end flange at the cable end of'the plug, and a cable clamp having a member surrounding the neck of the plu and a second member projecting beyond t e end of theplug into position to grip the cable to ether with means for clamping said secon member to the cable.

2. An attachment plug-having an insulat- I i in body with constrlcted neck and exterior en flange at the cable end of the plug, said end flange having a channel leading to the neck of the plug, in combination with a cable clamp having amember surrounding the neck of the plug, a. second member rojecting beyond the end of the plug into cable-gripping position, and abridge member lying in said end flange channel and serving to connect said neck and cable-grippingzmembers.

3. An attachment plug having an insulating body with constricted neck and end flange 'at-the cable end of the plu -,.and a cable clamp having a loop surroun in the -neck of the plug and a. second loop 0 less diameter projecting beyond the end of the plug into cable-gripping position together with draw-up means for clampin said 100 s respectively to the plug neck and the purpose described.

In testimony whereof I have signed my name to this specification.

cable, or v I WILLIAM A. STACEY. 

